- ONTAP 9
- Data ONTAP 8 7-mode
Note: There are more complex scenarios like multiprotocol access (CIFS and NFS) which are not covered here.
- Locks set by Network File System (NFS) clients are not enforced
- A client may gain access to a locked file, or to part of a locked file, depending on whether the client checks for and observes the lock
- This only applies to NFSv3 using NLM, but NFSv4 has a mandatory locking infrastructure
- Locks set by CIFS/SMB clients are enforced
- The locks affect clients, whether or not the clients check for the locks.
- If a lock exists, the client is denied the type of access according to the lock.
- If running the
dumpcommand on Data ONTAP 8 7-mode, it will ignore the file lock to finish the dump or NDMP backup.
How does ONTAP keep track of locks?
- Lock Manager (LMGR) is an ONTAP subsystem that implements file locking to manage concurrent access.
- It keeps track of which files are open and which locks are granted.
- This is handled in the Data/WAFL layer of ONTAP
- Each node on an ONTAP 9 cluster has its own lock manager running that manages the volumes located on aggregates owned by that node.
- Note: In 7-mode this is per controller
- To accomplish these tasks, a series of memory structures (objects) are allocated to the lock manager; the amount of these structures depends on the amount of memory installed on the storage controller and is fixed.